Tools company Dormer Pramet has developed a new range of chipbreaker inserts with positive NF geometry for the process of turning stainless steel.

The double-sided inserts, marketed under the Pramet brand, are available for the processes of finishing to medium-turning of stainless steel, low-carbon steel and super alloys. More than 110 variations in insert shapes, including C, D, S, T, V and W, sizes and grades have been developed.

Dormer Pramet turning product manager Josef Bittner says the balanced shape of the chipbreaker provides a stable and sharp cutting edge, with a large area for chip formation and evacuation from the cutting zone. Further, its positive geometry allows for low cutting forces and minimises vibration.

“The combination of these features promotes insert durability and reliability, enabling good productivity and a quality machined surface finish for the end-user,” he says.

The new inserts will be of interest to companies performing general turning applications, as their low radial cutting force values make them suitable for unstable machining.

Meanwhile, Dormer Pramet also announced the launch of new wiper inserts for turning with W-MR geometry.

Available in CNMG12, DNMG15 and WNMG06 and 08 inserts, W-MR is suitable for the longitudinal and face turning of steel, stainless steel and cast iron.

The double-sided inserts have a positive chipbreaker and a new shape on the smoothing edge to achieve low roughness in turning. This enables reduced cutting forces and higher feeds, increasing productivity while retaining the same surface finish as with standard inserts.

If used correctly, their use can completely eliminate the need for grinding, Dormer Pramet says.

The NF and W-MR geometry inserts further strengthen Dormer Pramet’s portfolio for machining stainless steel, with a wide range of indexable and rotary products now available.

Dormer Pramet’s additions to its turning range form part of a wider product launch that took place on April 1 and was the company’s first combined unveiling since Dormer and Pramet merged in 2014.

Thread Milling Range
During the April launch, Dormer Pramet also introduced a comprehensive thread milling product range to provide a reliable and versatile threading option.

Available under the Dormer brand, each of the new cutters contained in the tread milling product range is recommended for machining most materials, including steel, stainless steel, cast iron, titanium, nickel, copper, aluminium and plastics.

An Alcrona Pro coating and solid carbide substrate provides a tough and wear-resistant structure, offering security and reliability, as well as increased performance and longer tool life.

Thread milling offers numerous advantages, compared with conventional threading, including increased reliability, smaller chips – supporting continuous machining – improved tool life and accurate tolerance adjustment. It is also suitable for dry machining.

The same cutter can be used for many materials and diameters, as long as the pitch is the same, while Dormer’s J200 and J205 ranges offer the additional possibility to chamfer, providing better quality and accuracy, compared with conventional taps.